Considering that ML and chess engines are now only starting, how about making a hybrid model of bitcoin mining and the cpu/gpu cost of analyzing chess games? That way one percentage of the energy consumed of the mining, on bitcoin or whatever, isn't immediately thrown out of the window.
Or maybe making a hybrid model of analyzing the DNA of embryos to find defects, and bitcoin mining for the same reason. One fact not many people know is that economy in ancient Greece, was something women were doing. Men when there was something we wanted, we made wars. I foresee that there will be a digital coin like bitcoin that people will use, and that is gonna start from the women only. We, men, are not cut out like this, exchanging of goods in a peaceful manner.